The challenge:
An aerial view of most cities will reveal rooftops that are flat, dull and lifeless.

Project description:
Green roofs are flat or gently pitched roofs that have been overlain with a growing medium, creating a habitat on what would otherwise have been a plain surface. They are also sometimes called living roofs or vegetated roof structures, and are possibly one of the most tangible elements of a sustainability strategy, being visible, natural and distinctive. In addition to providing an attractive, roof-level habitat, living roofs can also contribute to the management of surface water run-off, the mitigation of local air pollutants and the extension of the useful life of a roof membrane.

Planning background and demands:
Although green roofs are often a feature of low-impact green development,
the planning context for green roofs is increasingly becoming the redevelopment of urban brownfield sites as these sites represent the greatest opportunities to employ the potential benefits of green roofs.
Key issues that can be addressed, in part, by the specification of green roofs on urban brownfield development, include:
- Control of stormwater run-off in response to constraints on peak flow capacity in the drains and loss of porous land surface through redevelopment
- Negative effects of increased development density, including poor quality urban microclimates
- Loss of valuable habitats for flora and fauna that have increasingly
colonised derelict urban land
- The need for green space in dense developments

Green roofs can, therefore, form part of a designer’s armoury of solutions
which combat some of the implications of urban development. Recently, though, with energy efficiency and on-site renewables dominating
the popular agenda, these roofs could end up at the bottom of a long list of sustainable options.

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